Great D.O.T.D. @ P.E. TB 5.25 woofer...

[critofur]

This was already the "Value Leader" of Zaph's ~ 5.5" woofer roundup at $25, now, it's on sale for $15 ea!

http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=264-850&dotd=012508&orefer=dotd&orefer=dotd

I'd been planing on buying some for a while now and just hadn't gotten to it. Tonight, I was ready to go "check out", I had some "in my cart" over at Amazon.com 'cause I had some gift certificates to use and when I saw the price I was pleasantly very surprised and thought it must be a pricing glitch or something. I headed over to partsexpress.com to check it out then saw on the front page "deal of the day". So, I ordered four instead of two

Heh, I'm going to be building some great sounding speakers for a total of $25 in parts for each speaker (I got a pile of capacitors and a few nice baltic birch plywood boards as a gift, the tweeters I'll use I got for $10).

 

[14G-Dutch^]

I looked @ TB's website, the driver changed and is now different, not shielded for one, and the FR is supposedly up to 9K now. I got 8 of them. gonna do a .33 Cf vented, tuned to 60 Hz. I will probably cross them @ 3500 to my Vifa D27TG-05-06 tweeters.

Was screwing around today, and for the fun of it I popped them into a .25 Cf Sealed enclosure. Fairly large output in the bass area, didn't get very low, but these were designed for vented anyways.

Jon

 

[Jay_WJ]

I looked @ TB's website, the driver changed and is now different, not shielded for one, and the FR is supposedly up to 9K now. I got 8 of them. gonna do a .33 Cf vented, tuned to 60 Hz. I will probably cross them @ 3500 to my Vifa D27TG-05-06 tweeters.

Was screwing around today, and for the fun of it I popped them into a .25 Cf Sealed enclosure. Fairly large output in the bass area, didn't get very low, but these were designed for vented anyways.

Jon

They should work for both sealed and vented. When used in a sealed box, they will give a perfect bass rolloff to be used with a subwofer at 80 Hz crossover setting on a HT receiver.

.33 cu ft will be a bit less than ideal for this driver. .5 cu ft will be better for vented.

With the Vifa, I'd shoot for 2 k to 2.5 kHz LR4, or 2.5 k to 3 kHz LR2.

 

[John L]

Jay, is your crossover you published at PE still up to date?

 

[Jay_WJ]

My xover simulations used Zaph's old data for W5-704S.

But according to the TB's new spec sheet, the 704D's frequency response and impedance curve are very similar to the 704S's. I actually compared the 704D's measured impedance curve to the one I used for modeling. They are very, very close up to 2 kHz. Since I used a Zobel in the xover, minimal differences at higher frequencies won't matter, either. As for the FR, usually TB's published FR is a few dB higher than actual one. The 704D FR on the spec sheet is very similar to Zaph's 704S FR except only 1 to 2 dB higher. So, my simulation should be pretty much in the right ball park.

A major difference between the new and old drivers is in their T/S parameters. The old one was suitable for a sealed design with high Qts, but the new one, according to a few sample measurements, has a bit less Qts making it suitable for both sealed and vented. But a vented design still requires a bit larger volume than people may want for a 6" driver.

-jAy

 

[14G-Dutch^]

They should work for both sealed and vented. When used in a sealed box, they will give a perfect bass rolloff to be used with a subwofer at 80 Hz crossover setting on a HT receiver.

.33 cu ft will be a bit less than ideal for this driver. .5 cu ft will be better for vented.

With the Vifa, I'd shoot for 2 k to 2.5 kHz LR4, or 2.5 k to 3 kHz LR2.

Jay,

Why .5? WinIsd models what looks better to me, admittedly a noob, with .33, which gives an f3 of 61Hz. The .5 seems to give a lower response capability, but to me it looks like I would be losing almost 2 Db between there and gradually less on up to 100Hz.

Would you mind explaining your idea to me?

Also, why would you cross this tweeter that low? It has an Fs of 1000Hz

Vifa tweeter specs

Vifa recommends 3500Hz, and the woofer is pretty clean up till nearly 6k, so I am not seeing a reason to cross that low. Again, I am not well versed on all the ins and outs of design. I am sure you have a good reason for these thoughts, I just can't see them.




Thanks,

Jon

 

[Jay_WJ]

Why .5? WinIsd models what looks better to me, admittedly a noob, with .33, which gives an f3 of 61Hz. The .5 seems to give a lower response capability, but to me it looks like I would be losing almost 2 Db between there and gradually less on up to 100Hz.

Would you mind explaining your idea to me?

T/S values on the spec sheet aren't accurate. Take a look at:

http://www.htguide.com/forum/showthread.php4?t=28829&page=1

Find measured T/S parameters in posts #22 and #30. Try to use them in your WinISD sim.

Also, why would you cross this tweeter that low? It has an Fs of 1000Hz

Vifa tweeter specs

Vifa recommends 3500Hz, and the woofer is pretty clean up till nearly 6k, so I am not seeing a reason to cross that low. Again, I am not well versed on all the ins and outs of design. I am sure you have a good reason for these thoughts, I just can't see them.

Again, don't rely on the manufacturer's spec sheet. See Zaph's distortion measurement:

http://www.zaphaudio.com/tweetermishmash/D27SG15-HD.gif

The D27TG05 performs identical to the D27SG15. According to Zaph's HD sweep, this tweeter is a very nice performer. 2.0 kHz LR4 is no problem with it. Fs at 1 kHz won't matter, either, for LR4 application even without a notch filter. You can simply use an L-pad before the tweeter and it will take good care of the resonance. For LR2, you may need a notch filter.

Considering the 6" woofer's beaming and CTC spacing between the drivers, a lower xover point will give a more robust vertical polar response.

 

[John L]

Jay, is this one still good to go, using the Vifa D26NC55? Or does it need modifications considering the new types?

An externally hosted image should be here but it was not working when we last tested it.

 

[Jay_WJ]

Jay, is this one still good to go, using the Vifa D26NC55? Or does it need modifications considering the new types?

Strictly speaking, I can't be 100% sure till I see a FR measurement of the new 704D. But I'm pretty confident that it is good to go with tweaking only the R9 value to adjust the tweeter level.

 

[John L]

thanks. This is the one I am going to go with. I like that idea of the TB tweeter, but the sticky surface is a turnoff, as John K mentioned.

 

[14G-Dutch^]

Thanks Jay,

Could my tweeter be used with that Xover in place of the D26NC55?

I am doing the mtm also

Jon

 

[John L]

Thanks Jay,

Could my tweeter be used with that Xover in place of the D26NC55?

I am doing the mtm also

Jon

Interesting, John K never tested the D27TG-05-06. Where did you get it?

Oh, wait a minute. They must be a discontinued line, that look exactly like the D26NC55s. I see that they are selling on E-Bay right now. I don't know much about the D27s, but do know that the D26s are one of the best all round tweets out there for the money.

 

[14G-Dutch^]

Interesting, John K never tested the D27TG-05-06. Where did you get it?

Oh, wait a minute. They must be a discontinued line, that look exactly like the D26NC55s. I see that they are selling on E-Bay right now. I don't know much about the D27s, but do know that the D26s are one of the best all round tweets out there for the money.

Interesting, there is no similarity actually afaik, the ones on ebay have been trimmed, so they only look the same.

I got them at PE 10 years ago. They look just like the Vifa-D27TG-05 that are currently sold, they are probably exactly the same.

Jon

 

[Jay_WJ]

Thanks Jay,

Could my tweeter be used with that Xover in place of the D26NC55?

I am doing the mtm also

Jon

No, you can't use your tweeter with my xover. You can use the low pass network for the woofers, but the high pass filter must be redesigned.

 

[14G-Dutch^]

No, you can't use your tweeter with my xover. You can use the low pass network for the woofers, but the high pass filter must be redesigned.

I was hoping your reply would be longer, hint hint....




Jon

 

[John L]

Joh, if it's any consolation, you can also use another tweeter with this driver. It's not your tweeter, but the TB 25-1166 is less expensive. Here is Jay's work-up on it from another forum.

An externally hosted image should be here but it was not working when we last tested it.

The cabinet size of 2/3 to 3/4 cu ft would work perfectly for either closed or ported. I did up the port length earlier, but forgot it. Somewhere like 3" diameter X 5.56" long,....I think.

The only real complaint with the TB tweeter is that the fabric dome is finished with a sticky substance that will tend to attract dust over time. Otherwise, it's a logical fit, since driver And tweet would have been made with each other in mind.

 

[Jay_WJ]

I was hoping your reply would be longer, hint hint....




Jon

Sorry, Jon, I'm not interested in doing more sims on this.

 

[critofur]

If you search for Tang Band W5-704 you don't find this thread, so, I'm posting a message with that driver name since this is a good thread for anyone looking for info about the TB driver.

The design w/the D26NC55 looks nice. I might buy a couple of those tweeters before they're gone...

It would be an interesting experiment to compare that crossover to a simpler series crossover in some A/B testing...

In regards to "sticky coatings" - I haven't found the dust that sticks to affect the FR much... Maybe they should pre-apply some black fuzz to all the sticky coated tweeters to prevent grey dust from sticking later...

edit: Has anybody built any of the TB W5-704 designs other than the "Aerial" dipoles over on the HTGuide forum?

 

[John L]

A couple of things I picked up on.

First, Jay's drawing is set up for the TB tweeter, which is round. The Vifa is not, and will look like cr@p off to the side. As for me, I will not do it that way, but most likely play around with the face plate, in order to make it look like the drivers go hand in hand.

Second, I used WinISD to check on the box size for closed and ported. I noticed that both came out almost identical for optimum size. That gives us a lot of leaway here. Ideal is something like .67 cu ft. So you don't have to be exact on size. Probably the best thing to do will be to build for the .75 cu ft, and then brace the inner cabinet very well, which will take up more space.

I just thought I would mention this.

Boy, are we heavily censored here,............or what!? Since when is "Cr a p" a bad word? Are we going overboard here?

 

[14G-Dutch^]

A couple of things I picked up on.

First, Jay's drawing is set up for the TB tweeter, which is round. The Vifa is not, and will look like cr@p off to the side. As for me, I will not do it that way, but most likely play around with the face plate, in order to make it look like the drivers go hand in hand.

Second, I used WinISD to check on the box size for closed and ported. I noticed that both came out almost identical for optimum size. That gives us a lot of leaway here. Ideal is something like .67 cu ft. So you don't have to be exact on size. Probably the best thing to do will be to build for the .75 cu ft, and then brace the inner cabinet very well, which will take up more space.

I just thought I would mention this.

Boy, are we heavily censored here,............or what!? Since when is "Cr a p" a bad word? Are we going overboard here?

Well now, that really sucks. The whole reason I bought these was it looked from the Tb specs as though I could use a small enclosure.